Stories of the

Often times, field guides are great for identifying unknown intertidal plants and . However, interesting stories about these organisms are left out. The following compilation of information comes from stories shared verbally and in written text. These stories are great to tell during guided inquiry and even in the classroom before a fieldtrip to the tidepools. Knowing the information or having it handy to share with students will make the tidepools come alive.

Phylum Porifera - filter feeding colonies

Sponges Sponges may look like simple plants, but many are surprised to find out that they are animals. They are relatively simple, but can grow in all shapes and sizes depending on where they live. Sponges growing in calm water tend to have more tube and volcano like structures. In the intertidal however they will often grow very flat due to high surf action. Sponges use many tiny holes called ostia to suck in seawater and shoot it out larger volcano openings called oscula. While the water is within the sponge it filters out all of the tiny organic particles, like bacteria, to feed and other nutrients needed for growth. That would be like humans surviving off of air alone!

Phylum Cnidaria - animals with stinging cells called nematocysts. These nematocysts work like high-powered barbs at the end of coiled ropes that shoot off when touched. These allow the to take hold of its food or defend itself. Nematocysts found in the intertidal will most likely not hurt you. Feel free to touch anemones, but it would be wise not to taste them.

Giant green anemones – Anthropleura xanthogrammica

There are many varieties of anemones in the tidepools, and while they all have special characteristics that separate them by , they share some really cool characteristics that make them similar. Most anemones found in the intertidal are green. One may ask why? Green anemones actually have tiny plants that live in their tentacles and columns. The plants have chlorophyll pigments that cause the anemone to turn green. The relationship between the anemone and algae is symbiotic, which means that both organisms benefit. Animals, even aquatic ones, require oxygen to breath. Respiration turns this oxygen into carbon dioxide, which the algae then take up and use for photosynthesis, which gives off oxygen as a waste. By hosting the algae within, the anemone has easy access to the precious oxygen. In addition to providing readily available carbon dioxide, the anemone’s body makes it a great home with built in stinging cell protection. If you search the underside of rocks or shady cracks you might be able to find white anemones. These are animals without algae in their bodies. It is not unhealthy; it just does not rely on symbiosis to get any of its oxygen.

Cloning anemones/aggregate anemones - Anthopleura elegantissima

When these anemones find themselves living alone on a bare rock, they will clone in order to reproduce. The anemone will pull itself apart for about two days until it rips in half. It will continue this process of cloning until it runs out of room. If it runs into another group of aggregate anemones that have been busy cloning as well, war will erupt between the two colonies. The anemones along the battle line will produce what are often called “war clubs,” tentacles that swell up on the ends with nematocysts. These two colonies will fight back and forth until there is a space between them with no anemones inhabiting it. This is why you can see dividing lines between all of the groups of aggregate anemones on the rocks during low . Often times these anemones cover themselves with small rocks; these rocks are used in a similar way to sun block, protecting them from the sun and helping them retain water at low tide.

Brooding anemones – Epiactis prolifera

Brooding anemones come in different hues of colors including bright red. Their bodies are flattened at the base with radialy arranged lines. Unlike the giant green and aggregating anemones, this animal relies on motherly tactics to raise their young. The anemone’s larvae swim out of their mom and position themselves along the flattened base. They stay there until they grow into tiny anemones and are ready to leave the home base. When you flip over a rock look for smaller anemones nearby the mother anemone.

Phylum – animals with a belly-foot

Black turban snail – funebralis

Looking for snails in the tidepools can sometimes be tricky. Don’t be surprised if you pick one up and it’s actually a ! Hermit are notorious for using black turban snails’ old shell as their home. Snails are part of the “belly-foot” family, meaning that they eat, move, and stick to rocks with their strong, fleshy body. Most snails are vegetarians and feed on algae or seaweed. The white circle on the top of the shells is actually the oldest part of the snail. It can live to be more than 20 years old, which is when it is no longer black on top. Sometimes you will see , limpets or smaller snails on the backs of black turban snails as well.

Purple – biplicata

Just like the black turban snail shells, purple olive snail shells in the intertidal are often found with hermit crabs within them. Purple olive snails live in sandy beaches about an inch or so underneath the sand. If a sandy beach is nearby the tidepools you will likely see a making one of these beautiful shells into their home. Miwok Indian tribes of the northern California coast and Chumash Indian tribes of southern California’s channel islands used these beautiful shells as money for trade and decorations on clothing and jewelry. Imagine begin able to go out and collect dollar bills on the beach! If you look closely on the shell you will see very fine lines showing the pattern of growth. The oldest part of the snail is at the very top of the spiral. The snail puts on tiny layers each year as it grows more and more. Sometimes people ask how old many of the creatures of the tide pools are. This is a rather difficult question to answer, but we can get some sense by looking at the number of lines on the purple olive snail. Some snails you pick up will have varying patterns. Some of the lines are very straight while others are very jagged. The jagged lines may indicate a rough point in the snail’s life where maybe they were attacked or lived through a rough winter. The smooth lines indicate an easy year for the snail. By reading the lines we get a story of this snails long-lived life experiences.

Chitons

Chitons have remained virtually unchanged for over 500 million years! There’s one thing that you must remember in the search for chitons: “eight plates are great!” Just like terrestrial pill bugs, chitons have hard plates that protect their body’s “belly-foot” and let them conform to uneven surfaces. A chiton can be motionless and uninteresting to the untrained eye, but if you manage to find one that lets loose from the rock, you’ll discover something interesting and familiar. When removed from the rock, chitons will curl into a crescent moon shape in order to protect the soft foot inside. The Katy chiton is often found exposed during the day, feeding on algae while most chitons are found in crevices and under rocks. Other chitons may remain in the same place for a long time while Katy chitons graze during the day. The is especially interesting. Unlike smaller species found in the intertidal, the gumboot can be easily dislodged and examined. In the gill chamber beside the belly foot of the gumboot is a small white parasitic worm that has found a safe home.

Nudibranchs

Keep your eye out for these small creatures. Often overlooked, over one hundred and seventy nudibranchs can be found along Pacific Northwest shores. They are essentially snails with out shells, but often much more colorful than our common garden slugs. They come in a variety of colors including lemon yellow, bright red, orange and even purple! Many nudibranchs are often missed though because they can be translucent in color making them nearly invisible. The name nudibranch actually means “naked gills”. Some species use finger like cerata on their backs for breathing and digesting food! The cerata can also be used for defense. Many nudibranchs feed on the tentacles of sea anemones to steal their nematocysts. Because they have special mucus to protect them, they are not harmed by the harpoon-like stinging cells. The nudibranchs simply gobble them up and sort the stinging cells for all of the cerata. The nudibranchs are then armed with the weapons of their prey! Other nudibranchs lacking cerata have gill plumes located on their lower end. Like every little brother or sister nudibranchs are picky eaters and feed almost exclusively on colorful sponges.

Limpets

It’s impossible to find two limpets that look identical. Their variety in colors and patterns make searching for them an adventure with something new under each rock. Limpets rely on their powerful suction power to protect them from predators and pounding waves. In fact pounding waves only allow the limpet to hold tighter onto a rock. These simple creatures also have the ability to sense when an enemy, usually a sea star, is around. When the situation arises, they can glide away with their shell hiked up like a big southern bell skirt. The alternative is to just let go of the rock and fall out of harms way. Most limpets are vegetarians and graze on thin layers of algae that grow on rocks. Their sandpaper-like tongue extends to the rocks and conveys the broken up food particles into their mouth. Limpets have a designated home territory where it cruises around during high tide. When the water recedes, some species even nestle into a “home-scar”, which over time they have carved into the rock.

Mussels

You will most likely find mussels living in large clumps. Where a young mussel chooses to settle will determine the length of its life. Too high and it will die from dehydration, too low and it will get eaten. Most choose a place that already has adults present. Once a young barnacle has found the right spot, it attaches itself with strings made of protein called byssus. These byssal threads are elastic bands secreted by a gland that provide it with limited movement. They are also what allow us to wiggle them like a loose tooth. When the tide comes in the animal replenishes itself with oxygen rich water while it collects plankton for its meal. It does this by siphoning water and pulling it over its gills, which collect oxygen and food simultaneously.

Phylum Echinodermata – animals with penta (5) radial symmetry

Ochre stars – Pisaster ochraceus

You might know this animal as a , but this is a misconception because the sea star is most definitely not a fish. Also called an ochre star, the common sea star can be divided into five equal parts, and can even regenerate lost arms. Following the path of a sea star can become very confusing because it can move in whatever direction one of its arms points it in. Not having a head or tail allows it to switch directions without turning around. The underside of the animal is covered in tube feet, which move it along at three inches a minute. The tube feet at the very tip of each arm don’t suction, but are light sensitive to the animal can move out of direct sunlight. Aside from locomotion, the sea star’s tube feet allow it to hold onto a rock, which protects it from harsh waves. The stomach of a sea star is exerted from the animal’s underside when it’s time to eat. It can slip into crevices to find and pry apart delectable morsels like mussels, limpets, and snails. The stomach juices dissolve smaller animals outside of the sea stars body, and the resulting liquid is then absorbed. So you could say that the sea stars like to literally eat out for every meal!

Sunflower star – Pycnopodia helianthoides

With the ability to move up to 40 inches per minute, the sunflower star navigates the subtidal and intertidal with up to 24 arms and over 15,000 tube feet! The sunflower star is hungry predator, eating crabs, sea cucumbers, snails, chitons, and sea urchins. When the tide is low, you can see these soft skinned, colorful creatures hanging out in shaded areas of the pools. If the sunflower stars are in the sun, you can see small light sensors (they look similar to the tube feet, but smaller) on the ends of their arms that will navigate them out of the sun to avoid the dangers of drying up in a shallow tidepool.

Purple sea urchins – Strongylocentrotus purpuratus

The spiky purple spines and tube feet of the sea urchin serve numerous purposes. The hard spines help attach food and protect the animal from predators. The sea urchin can also rise up onto the ends of the spines and walk away like they are on stilts. Their tube feet allow them to pass bits of food down to the mouth, which lies on the underside of the animal. In addition to being an aid in food digestion, tube feet are also the site of gas exchange: instead of using lungs or gills for the uptake of oxygen, sea urchins use their tube feet. Purple sea urchins prefer areas with strong wave action. To protect themselves from especially harsh waves, they can carve individual holes in the rock in which they settle. The holes may take generations to dig, but it provides for excellent protection from waves and predators. It also makes eating easy, as each wave delivers it meals of algae, seaweed and plankton. In some cases a sea urchin can grow bigger than its home, make it stuck for life in the rock. Many animals find sea urchins to be irresistible. Sea stars, sea gulls, and sea otters find them to be a tasty treat. It’s easy to pick out a that regularly eats purple sea urchins because of their purple stained teeth. Even people find the gonads of the animal to be a delicacy! Humans can use sea urchins as an indicator of water health. Since they are one of the first organisms to show signs of stress in less than perfect water conditions, the loss of urchins from an area is a good indicator that something may be wrong with the water.

Phylum Arthropoda – animals with segmented legs (including crustations

Hermit crab – Pagrus spp.

Pick up a snail shell in the rocky intertidal and you’d be surprised that it is actually a hermit crab! Not having a home of its own, a hermit crab will spend its lifetime searching for the perfect lodging. Its keen sense of smell leads it to the shells of dead gastropods. As their soft vulnerable body grows, it requires bigger and bigger shells. In a hermit crabs busy life of finding new mobile homes and food, it’s hard to find time to mate. When a male finds a female in which he is willing to fight over, he carries her around until it is time for her to molt. At this point, they both release almost completely from their homes and mate. Two appendages on the left side of her body, called “swimmerets” hold the fertilized eggs until the young are released from the shell and into the water. Through evolution, hermit crabs have lost some legs, but kept the dominant two pairs that are used to grab shells and secure the animal into new homes.

Purple shore crab – Hemigrapusus nudus

The purple shore crab is one that you will always be able to find. It is distinguished by the reddish-purple spots on its claws. Don’t be fooled though, the main body color can vary greatly. Purple chore crabs feed primarily on seaweed and algae, but will occasionally enjoy a dead animal carcass every now and then. Their main predators are shorebirds and some fish. As crabs grow, they must molt their shells that are too small. During this time they are especially vulnerable as prey. Crabs are distinctly male and female. You can tell the difference by the shape of their underside. The male’s abdomen is V shaped while the female’s is U shaped.

Phylum Chordata – animals with a backbone

Tidepool sculpins – Oligocottus maculosus

These small fish are very adapted to the tidepools; they hug the bottom of the pools and are able to use their fins to scoot around. When the tides are high, the sculpins leave their home pools to search for food in the upper intertidal pools. When the tides begin to fall, they return to their home pools! It is unknown how they are able to return to their specific pool, but it is hypothesized that it is through the use of smell. Returning to a home pool is a safety mechanism for the sculpin, assuring that they will not get stuck in a water-less pool too high in the intertidal. Tidepool sculpins also have the ability to camouflage to their pools to help them hide from any hungry birds above.

Black oystercatcher – Haematopus bachmani

Oystercatchers forage at low tides on a variety of intertidal animals, but especially on mussels and limpets. As a mussel gapes open when splashed by a rising tide, they are vulnerable to oystercatcher . The bird must deliver a quick, sharp stab between the two shells and sever the adductor muscles so that the mussel doesn’t close down on the oystercatcher’s beak. Once inside, the oystercatcher will withdraw the meat and swallow, yum! With limpets, a true treat, oystercatchers will jab at the edge of the shell in order to dislodge the limpet from a rock. The oystercatcher will then shake out the meat and swallow it in one gulp. Look for empty limpet shells that have a nick out of their edge. This is a sign an oystercatcher has eaten them.

Algae – not true plants because they don’t produce flowers or seeds

Bull kelp – luetkeana

Bull Kelp grows tall in Pacific Northwest subtidal zones creating diverse kelp forest communities underwater. Think of all of the species this plant provides homes for! Bull kelp grows annually starting as a new plant each year on the sea floor reaching up to the sunlight rich surface. At the end of the growing season the 70-foot long plants will wash ashore, entangled from the waves. However you are likely to find bull kelp washed up as the growing season continues. The root like holdfasts are strong and will often have rocks still attached with their strong grip. The long stem, called a stripe, extends up to a large bulb float. This hollow float was used by coastal Native American tribes as a bowl or cup to carrying water. The stripes were also dried and used for fishing line. It was also pickled and eaten by early pioneers. They can also make a great jump rope!

Laver or nori – Porphyra perforata This red seaweed catches the sunlight beautifully on a clear day showcasing its iridescent qualities. This plant dries up quickly in the high tide zones, but can easily re- hydrate once the tide comes back up. This is the same plant used to make sushi nori, which is baked into sheets, and is cultivated worldwide as food. Pick a small piece and taste it!

Rockweed – Pelvetiopsis limitata

Rockweed is the Northwest’s most commonly seen algae. It grows on rocks in the intertidal instead of stretching up from the ocean’s floor like its much larger cousin bull kelp. The button-like holdfast keeps the algae from drifting away from its rocky substrate. Rockweed holds moisture extremely well so it can withstand drastic changes in temperature. Tannins, a chemical released by the algae, prevents it from being eaten by hungry tidepool creatures. The small bumps on the swollen ends of rockweed are sites of reproduction. It chooses the perfect time at low tide to release the eggs and sperm from the bulbs. The developing plant must eventually attach to a rock and grow a new holdfast.

Coralline Algae - Corallina, Callirarthron and Bosiella spp.

Don’t fool this plant, or any other plants in Oregon’s rocky intertidal for coral. While these algae may look like a hydrocoral, it’s actually coralline algae, which means that it is a plant and not an animal. In the water they are vibrant pink, but above water for long periods of time they turn white. What you are seeing when it’s white is the calcium carbonate that comprises their cell walls. Calcium carbonate is the same stuff that you bones are made of. Take off a piece and try crumbling it in your fingers, its tough! It provides structure and tough enough to withstand storms and repels grazing animals.